High-voltage generator



March 3, 1953 G. c. SZIKLAI YETAL 2,630,549

HIGH-VOLTAGE GENERATOR Filed Aug. 51, 1948 .D. C 01/7/ 0 7' V0! 77165- INVENTOR S Banner-z E. SzmLm 5 ALFB 0E. SEHHD DEB B! i}; u;

ATTORNEY Patented Mar. 3, 1953 2,630,549 HIGH-VOLTAGE GENERATOR George C. Sziklai, Princeton, N. J., and Alfred C. Schroeder, Feasterville, Pa., assignors to Radio Corporation of America, a corporation of Delaware ApplicationAugust 31, 1948, Serial No. 46,946

6 Claims. (01. 315-39) This invention relates to improvements in high voltage generators, and more particularly to improved means for obtaining very high unidirectional voltages.

It is one object of the present invention to provide improved means for obtaining high unidirectional voltages from a low voltag source.

Another object of the invention is to provide improved means for obtaining very high unidirectional voltages without the use of transformers or conventional rectifiers.

A further object of the invention is to provide an extremely efiicient high voltage generator.

According to the invention, the foregoing and other objects and advantages are attained by combining a magnetron oscillator with an electron accelerator in a common magnetic field. The magnetron oscillator may be any one of the many well known types of high frequency generators in which electrons emitted from a thermionic filament or cathode are deflected by a magnetic field to produce high frequency energy, while the electron accelerator, as the term is used herein, is to be taken to mean a thermionic device in which electrons are constrained to move in a spiral by a constant magnetic field, while being continuously accelerated by an alternating high frequency electric field acting at right angles to the magnetic field. The magnetron may be operated from a relatively low unidirectional voltage source to supply the necessary high frequency energy to the accelerator. In the accelerator, the high frequency energy from the oscillator imparts very large amounts of kinetic energy to moving electrons which eventually strike a collecting electrode, giving the collecting electrode a very high potential, so that the device eifectively acts as a unidirectional voltage transformer. A more complete understanding of the invention may be had by reference to the following description of an illustrative embodiment thereof when read in connection with the accompanying drawing in which:

Figure 1 is a perspective view of one possible form of high voltage generator arranged in accordance with the invention, and

Figure 2 is an exploded view of certain parts of the device of Figure 1.

Referring to the drawing, a high voltage generator embodying the principles of the invention is seen to include a thermionic cathode Ill arranged to serve as a source of electrons for both the oscillator and the accelerator sections of the device. For simplicity, no heating means have been shown for the cathode 10, although in practice the cathode will ordinarily be heated by a filament or the like. Surrounding one portion of the cathode I0 is a segmented cylindrical. oscillatory anode comprising two semi-cylindrical sections I2 and I4 to which the conductors I6 of a resonant wire line system may be connected. An axial magnetic field is provided by means of a magnet, of which only the pole pieces N, S are shown. When unidirectional voltage from a suitable source 20 is applied between the anode segments I2, l4 and the cathode Ill, high frequency oscillations will be set up between the two anode segments l2 and H! in a well known manner. The high freouency energy developed in the oscillator section is to be utilized in the accelerator section of the device as will be made apparent hereinafter.

The accelerator section may consist of two pairs of D-shaped accelerating anodes 22, 23 and 24, 25 disposed Within a cylindrical collecting electrode 26. The anodes 2226 are all arranged to operate in conjunction with one section of the cathode 10. The two ad acent accelerating anodes 22 and 24 are connected directly to, and may be made unitary ith, the osc llator anodes l4 and I2 respecti ely, so that the high frequency voltage developed between the anodes I2 and I4 is supplied directly to the accelerators 22 and 24.

In order to provide the proper e ectric field distribution within the space bet een each pair of D-shaoed anodes 22. 23 and 24, 25, it will be appreciated that the anodes in any one pair must both be at the same alternating and unidirectional otential. Accordingly, the anodes in each pair are connected together by means of lines 28, 29 which are an integral number of full wavelengths long, or by other similar means. It will be noted that the same magnetic field which is established in the area between the cathode I0 and the oscillator anodes l2, l4, by the magnetic poles N, S, also passes between the cathode I0 and the anodes 22-26 of the accelerator section. The entire assembly may be disposed within an evacuated envelope 34.

In operation, when the oscillator anodes l2, l4 supply hi h frequency energy to the accelerating anodes 22-25, electrons emitted from the accelerator section of the cathode II) will come under the combined influence of the alternating electric field and the constant magnetic field, both of which will exist in the area between the accelerating an des 2225 and the cathode Ill. As a result. these electrons will follow a spiral path around the cathode, constantly gaining potential 3 energy and traveling further and further from the cathode until they finally strike the collecting anode 26. Since the electrons will, in general, be accelerated each time they cross the gap between the oppositely charged pairs of accelerating anodes, regardless of the kinetic energy possessed by the electrons at the time they cross the gap, it will be seen that the potential to which the collecting anode may be charged is many times greater than the greatest difference in potential which will ever exist between oppositely charged pairs of accelerating anodes. In general, for an arrangement of the kind shown in the drawing, it will be found that the output voltage is a function of the square of the diameter of the accelerating anodes 22, 25. Electrons will continue to reach the collecting anode 26 until a a balance is reached between the kinetic energy of the traveling electrons and the potential energy of the collecting anode. The system will then remain in equilibrium, with no more electrons reaching the anode 26, until some of the charge is drawn ofi through the output terminals 30, 32. It should be noted that the radius of the accelerating anodes 22-25 should be made less than an eighth wavelength at the selected operating frequency to avoid the adverse effects of having large phase dilferences at any instant along the edges of the accelerating anodes next to the gap.

It will be understood that the arrangement shown and described is only one very simple embodiment of the invention chosen for illustrative purposes. It is obvious that the magnetron oscillatormay be any one of the many known types of such oscillators, while the number of the accelerating anodes, as well as their exact shape, spacing, and relative arrangement is subject to considerable variation. Moreover, the oscillator and accelerator sections can either be made in a composite structure, as shown, or could as well be constituted as separate elements mounted to operate in a common magnetic field.

Since these and many similar changes and modifications could be made in the arrangement shown and described, all within the scope and spirit of the invention, the foregoing is to be construed only as illustrative, and not in a limiting sense.

What is claimed is:

1. A high, unidirectional voltage generator comprising a magnetron oscillator including a plurality of oscillatory anodes and means for establishing a magnetic field for said oscillator, an electron accelerator including a cathode, a plurality of accelerating anodes, and a collecting electrode, said accelerator being disposed in said magnetic field, and means coupling the output of said oscillator to said accelerating anodes comprising connections between selected ones of said oscillatory anodes and selected ones of said accelerating anodes.

2. A high, unidirectional voltage generator comprising an envelope, a magnetron oscillator in said envelope and including means for establi'shing a magnetic field for said oscillator, an electron accelerator in said envelope and including a thermionic cathode, a cylindrical collecting electrode arranged coaxially with said cathode and surrounding said cathode, and a plurality of accelerating anodes disposed within said collecting electrode, 'said accelerator beingdisposed within said magnetic field, means coupling the output of saidoscillator to said accelerating 4 anodes, and means for deriving a high, unidirectional voltage between said cathode and said collecting electrode.

3. A high, unidirectional voltage generator comprising an envelope, a magnetron oscillator in said envelope and including two oscillatory anodes and means for establishing a magnetic field for said oscillator, an electron accelerator including a thermionic cathode, a cylindrical collecting electrode arranged coaxially with said cathode and surrounding said cathode, and a plurality of D-shaped accelerating anodes disposed within said collecting electrode, said accelertor being disposed within said magnetic field, and in said envelope, and means coupling the output of said oscillator to said accelerating anodes comprising connections between selected pairs of said accelerating anodes and selected ones of said oscillatory anodes.

4. A high, unidirectional voltage generator comprising an envelope, a magnetron oscillator in said envelope and including oscillatory anodes, means for establishing a magnetic field for said oscillator, and an electron accelerator in said envelope and including a cathode, a plurality of accelerating anodes, and a collecting electrode, selected ones of said oscillatory anodes being made integral with selected ones of said accelerating anodes, and said magnetic field being common to said oscillator and said accelerator.

5. A high, unidirectional voltage generator comprising an envelope, a magnetron oscillator in said envelope and including oscillatory anodes, means adjacent opposite sides of said oscillatory anodes for establishing a magnetic field for said oscillator, an electron accelerator in said envelope and including a cathode, a plurality of accelerating anodes, a collecting electrode, selected ones of said oscillatory anodes being made integral with selected ones of said accelerating anodes, said magnetic field being common to said oscillator and said accelerator, means in circuit with said oscillatory anodes to produce high frequency oscillations in said magnetron oscillator, and means to derive a high unidirectional voltage connected to said collecting electrode and to said cathode.

6. A high unidirectional voltage generator as defined in claim 5 wherein said means to produce high frequency oscillations comprise a resonant wire line connected across said oscillatory anodes, and means to apply a source of unidirectional voltage connected between said resonant wire line and said cathode, and said means to derive a high unidirectional voltage comprise a first output terminal connected to said cathode and a second output terminal connected to said collecting electrode. 7 e

' GEORGE C. SZIKLAI.

ALFRED C. SCHROEDER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,860,152 McArthur May 24, 1932 1,889,595 De Walt Nov. 29, 1932 2,187,172 Okabe Jan. 16, 1940 2,242,888 Hollmann May 20, 1941 2,265,113 Dick Dec. 2, 1941 2,563,585 Dallenbach Aug. 7, 1951' 

